Using various manual and automated systems and methods, whole blood is collected and separated into its clinical components (typically red blood cells, platelets, and plasma). The collected components are typically individually stored and used to treat a variety of specific conditions and diseased states.
Before transfusing the collected blood components to a recipient in need of the component, or before subjecting blood components to treatment (such as but not limited to pathogen inactivation), it is often desirable to minimize the presence of impurities or other materials that may cause undesired side effects in the recipient. For example, because of possible reactions, it is generally considered desirable to reduce the number of leukocytes in blood components before storage, or at least before transfusion (i.e., “leukoreduction”).
Filters are widely used to accomplish leuko-reduction in blood products today (e.g., warm and cold filtration of leukocytes from whole blood, red cells, and/or platelet products). Filters typically include a filter media disposed between mating walls of a filter housing. Inlet and outlet ports associated with the housing provide flow to and from the interior of the filter. The walls of the housing may be made of a rigid, typically plastic, material, although filters including soft housings are also known. Soft housing filters provide the advantage of being able to withstand handling and centrifuging without breakage of the filter. Examples of soft housing filters are disclosed in U.S. Pat. No. 6,367,634 issued Apr. 9, 2002; U.S. Pat. No. 6,422,397 issued Jul. 23, 2002; U.S. Pat. No. 6,745,902 issued Jul. 8, 2004; U.S. Pat. No. 7,353,956 issued Apr. 8, 2007; U.S. Pat. No. 7,332,096 issued Feb. 19, 2008; U.S. Pat. No. 7,278,541 issued Oct. 9, 2007; and U.S. application Ser. No. 10/275,805 filed Mar. 10, 2003, all of which are incorporated by reference herein. Due to the importance of filtering blood or blood components, there exists an ongoing desire to improve the construction, performance, and manufacturability of blood filters.